Electrophotographic cleaner flicker bar

Abstract: A cleaning apparatus including a rotary cleaning brush having a flicker bar (120) for removing particles from the cleaning brush. The flicker bar is a unitary member having an air channel (115) integral therein, along which a flow of air is established for carrying away removed particles. The unitary construction and support bars (200) in the top member of the flicker bar provide a uniform air channel width that is not compromised due to assembly tolerances.

Description: This invention relates generally to an electrostatographic printer or copier, and more particularly concerns a cleaning apparatus used therein. In an electrophotographic application such as xerography, a charge retentive surface (i.e. photoconductor, photoreceptor or imaging surface) is electrostatically charged, and exposed to a light pattern of an original image to be reproduced to selectively discharge the surface in accordance therewith. The resulting pattern of charged and discharged areas on that surface form an electrostatic charge pattern (an electrostatic latent image) conforming to the original image. The latent image is developed by contacting it with a finely divided electrostatically attractable powder referred to as "toner". Toner is held on the image areas by the electrostatic charge on the surface. Thus, a toner image is produced in conformity with a light image of the original being produced. The toner image may then be transferred to a substrate (e.g., paper), and the image affixed thereto to form a permanent record of the image to be reproduced. Subsequent to development, excess toner left on the charge retentive surface is cleaned from the surface. The process is well known, and useful for light lens copying from an original, and printing applications from electronically generated or stored originals, where a charge surface may be imagewise discharged in a variety of ways. Ion projection devices where a charge is imagewise deposited on a charge retentive substrate operate similarly. Although a preponderance of the toner forming the image is transferred to the paper during transfer, some toner invariably remains on the charge retentive surface, it being held thereto by relatively high electrostatic and/or mechanical forces. Additionally, paper fibers, Kaolin and other debris have a tendency to be attracted to the charge retentive surface. It is essential for optimum operation that the toner remaining on the surface be cleaned thoroughly therefrom. A commercially successful mode of cleaning employed on automatic xerographic devices utilizes a rotatable brush that frictionally engages the imaging surface to remove the residual toner and paper particles therefrom. In brush cleaners such as those in a xerographic cleaner where a rotating brush is used to clean (via mechanical, electrostatic, or other means) toner (or other particles such as carrier beads, paper fibers, etc.) from the photoreceptor (or any other surface for that matter), detoning (or cleaning) the brush is necessary. Air detoning is one method where an air stream is pulled through the brush fibers, carrying away toner (and other collected debris). To enhance the lessening of debris from the brush fibers in this type of system, flicking devices (one or more) are employed to disturb the fibers and a nearby air slot provides the air flow to pull away loosened debris. The mechanical flicking is accomplished by placing some type of "flicker", e.g. a round bar, in the path of the rotating fibers. The location of the "flicker bar" relative to an air slot, i.e. upstream and/or downstream may have different effects on the overall detoning performance, but will depend on the specific application. Typically, the flicker bar is considered a high wear item and requires replacement at specified intervals. Various problems exist with the present cleaner brush detoning systems. In some systems, a flicker bar may be positioned on one side of an air passage with the other side formed by a separate part, leading to assembly-to-assembly variations in the air passage size and negatively affecting air flow characteristics that can result in clogging of the air passage. When the air passage is clogged, additional servicing (beyond servicing of the flicker bar) is required to clear the air passage. Normally, the flicker bar can only be accessed after some degree of disassembly which results in high service costs. The following disclosures may be relevant to various aspects of the present invention and may be briefly summarized as follows: US-A-3,706,108 to Taylor discloses removing residual toner particles from a photoconductive surface using a rotating brush that contacts the surface. Removal of the residual toner particles from the brush fibers is assisted by applying a bias voltage to the brush to attract the toner particles to the brush and by using a flicker bar to loosen the toner particles from the cleaning blades. US-A-4,123,154 to Fisher discloses a cleaning apparatus wherein a flicker element removes residual material from a cleaner element. The flicker element works together with a corona charging device to neutralize the charge on the toner to aid in removal of the toner from the cleaning element. US-A-4,435,073 to Miller shows a cleaning brush with a plurality of flicker bars, at least one of which is fabricated from a material that will cause the charge on the brush to reverse at least once for every revolution of the brush, such reversal taking place while the brush fibers are subject to a toner removing airflow. US-A-4,304,026 discloses a cleaning brush arrangement in which a flicker member is adapted to have elongate apertures formed therein. A vacuum chamber is provided behind the flicker member to draw the air and toner particles through the elongate apertures. Briefly stated, and in accordance with one aspect of the present invention, there is provided apparatus for removing particles from a surface, the apparatus comprising: a housing; a rotatably mounted brush, at least partially enclosed in said housing and contacting the surface to remove particles therefrom; and a bar in contact with said brush for removing particles therefrom, said bar defining a channel therein adapted to have air with removed particles flow therethrough, characterised in that said bar is mounted slidably into said housing and in that said bar is of unitary construction. Other features of the present invention will become apparent as the following description proceeds and upon reference to the drawings, in which: Figure 1 is a perspective view of a cleaning system having slidably insertable flicker bars partially extending from the housing; Figure 2 is a perspective view of the slidably insertable flicker bar shown in the Figure 1 cleaning system; Figure 3 is an elevational view of the dual brush cleaners with the flicker bar therein; Figure 4 is an exploded partial sectional elevational view of a portion of the flicker bar. Although the flicker bar of the present invention is particularly well adapted for use in an electrophotographic printing machine, it should become evident from the following discussion, that it is equally well suited for use in other applications and is not necessarily limited to the particular embodiments shown herein. Reference is now made to Figure 1, which shows a perspective view of the cleaning apparatus 92 of a single construction slidable flicker bar therein. Figure 1 shows a dual cleaning brush cleaning system. The two rotatable brushes 100 are separated from each other by a separator 130 to keep the fibers from one of the brushes from contacting the fibers of the adjacent brush. A flicker bar 120 is slidably inserted into a channel, in the cleaning housing 145, above each rotatable cleaner brush 100. The flicker bar 120 extends the length of the rotatable brush 100 in the cleaning apparatus 92. There is an end plate 140 located at the end of the cleaning apparatus. The flicker bar 120 is removed from the channel in the cleaner housing 145 by an extended piece of the flicker bar that protrudes therefrom called a handle 121. The handle 121 is located on the front end of the flicker bar 120. This handle 121 provides an accessible means to remove and insert the flicker bar 120 into and out of the housing without high service cost disassembly. Reference is now made to Figure 2, which shows the slidably insertable flicker bar 120 of the present invention in a view opposite the view shown in Figure 1. The flicker bar 120 is single piece construction that contains an air channel 115 therein. The unitary construction of the flicker bar 120 provides a properly sized air channel and prevents a variable size air channel due to assembly tolerances that occur when more then one component is assembled to create an air channel. On either side of the air channel 115 are the channel walls 175, parallel to one another. The channel walls 175 flip outward forming wings 176 on either side that fit into the channel of the cleaner housing. The winged formations shown in Figure 2, form a flat flicker bar edge 170 facing toward the brush fibers on one side of the air channel 115 and a protruding flicker bar edge 180 on the opposite side of the air channel 115. The flat flicker bar edge 170 does not contact the brush fibers. The protruding flicker bar 180 extends into contact with the rotating brush to disturb the brush fibers. Other flicker bar variations of the present invention which are not shown include: having the air channel 115 followed by a single flicker (i.e. the protruding flicker bar end 180) rather than preceding the air slot as shown in Figure 2; having a protruding flicker bar edge 180 followed by the air channel 115 followed by another protruding flicker 180; and having no protruding flicker, but just an air channel. With continued reference to Figure 2, the top member 177 of the air channel 115 is perpendicular to the channel walls 175. The top member 177 contains support bars or spacers 200 that are intermittently placed along the length of the flicker bar air channel 115. These spacers 200 provide support needed to maintain the uniform width size of the air channel. Between the spacers 200 are air cavities or air slots 210 for the air entrained with toner (from the brush detoning) to flow from the air channel 115 into the air manifold 150 (shown in Figure 3). Reference is now made to Figure 3, which is a frontal elevational view of the dual brush cleaners 100 with the flicker bars 120 inserted therein. The brushes 100 rotate in the direction indicated by arrow 19. The brush fibers frictionally contact a belt photoreceptor 10, moving in the direction of arrow 12, to clean the surface. A backer roll 160 provides support for the photoreceptor 10. The particles removed from the photoreceptor surface that adhere to the brush fibers are removed, from the brush fibers, when the fibers contact the protruding flicker bar edge 180. The flicker bar dislodges the toner and other debris particles held in the brush fibers as the brush is rotating. The air passage 190 (see Figure 4) that is located after the flicker bar has a vacuum attached to the other end for removal of the dislodged particles away from the cleaner brushes 100. The air passage 190 carries the dislodged particles to an air manifold 150 which has a vacuum (not shown) on its opposite end creating the air flow that moves the particles away from the brush fibers. With continued reference to Figure 3, the brush cleaners 100 are followed by a spots blade assembly 230. The spots blade assembly 230 has a spots disturber blade 220 located downstream of the cleaning brushes in the direction of movement 12 of the photoreceptor 10, to disturb residual particles not removed by the brushes 100. This spots disturber blade is similar to that used in the Xerox (Trade Mark) 5090 copier. The spots blade disturber 220 is normally in the doctoring mode to allow a build up of residual particles between the brush cleaner housing 145 and the spots blade 220. This build up of residual particles is removed by the air flow of the vacuum. Reference is now made to Figure 4, which shows an exploded, partial view of the area marked by circle 4 in Figure 3. The flicker bars 120 are seated in the channel of the housing 145. The integral air channel of the flicker bar is uniform throughout the length of the flicker bar. The solitary construction of the flicker bar eliminates the nonuniformity due to assembly tolerances. In recapitulation, it is evident that the flicker bar provides optimal access for service actions and features an integral air channel therein to guarantee proper air channel size. The unitary construction of the flicker bar eliminates variance in the air channel width due to assembly tolerances. The spacers in the top member of the flicker bar provide support in maintaining the uniform flicker bar width for the air channel. The variations of the flicking mechanism as to location and number for detoning purposes can be varied as needed for cleaning.

Claims: Apparatus (92) for removing particles from a surface (10), the apparatus comprising: a housing (145); a rotatably mounted brush (100), at least partially enclosed in said housing (145) and contacting the surface (10) to remove particles therefrom; and a bar (120) in contact with said brush (100) for removing particles therefrom, said bar defining a channel (115) therein adapted to have air with removed particles flow therethrough, characterised in that said bar (120) is mounted slidably into said housing (145) and in that said bar (120) is of unitary construction. Apparatus as recited in claim 1, wherein the channel (115) of said bar is substantially uniform in width therealong. Apparatus as recited in claim 2, wherein said bar (120) comprises: first and second members (175) arranged substantially parallel to one another and each having an inner surface and an outer surface opposed from one another, said inner surface of said first member and said inner surface of said second member being opposed from one another; and a top member (177) arranged substantially perpendicular to and interposed between said first and second members (175) and connecting said first member to said second member to define the channel (115) between said first and second members (175) and said top member (177). Apparatus as recited in claim 3, wherein said top member (177) defines a slot (210) connected to the channel (115) to allow air and particles to pass therethrough from said brush (100). Apparatus as recited in any one of claims 1 to 4, further comprising means (150), coupled to said channel (115), for generating a flow of air therethrough. Apparatus as recited in claim 5 when dependent on claim 4, wherein said generating means (150) is connected to the slot (210) in said top member (177) to enable air and particles from said brush (100) to pass through the slot (210) into said generating means (150). Apparatus as recited in any one of the preceding claims, wherein said bar (120) comprises a handle (121) at one end thereof enabling said bar (120) to be inserted into and removed from said housing (145). Apparatus as recited in any one of the preceding claims, wherein the apparatus includes two rotatably mounted brushes (100) in the housing (145), the two brushes (100) being separated by a separator (130) and each having an associated bar (120).

Inventors: PARKS BRUCE J, VOUROS JOHN S, PARKS,BRUCE J., VOUROS,JOHN S.
Applicants: XEROX CORP, XEROX CORPORATION
Application year: 1994
Main classification: G03G21
IPC codes: G03G21